Although long, straight fluorescent lamps have the largest market share in lighting technology and have gained acceptance worldwide for many years, only a few significant improvements have been made in the further development of these lamps. These include the switch to electronic ballasts, a certain improvement in fluorescent material and a reduction in the diameter of the glass tube.
The high cost in the manufacture of lamps and light strips was perceived as a necessary evil and attempts were made to reduce the manufacturing costs by using terribly expensive robots. This primarily concerns the laying of millions of kilometers of connection lines in the lamps, whose electrodes must each be connected with two wires over the entire length of the lamps.
The task of the invention is to radically reduce this expense, and not only to save costs, but also to devise additional lamp designs and applications of these energy-saving fluorescent lamps.
This objective is achieved by equipping these long, straight glass tubes, that serve as gas discharge vessels, on one end in the region of the first electrode with all required connections for connection to the electronic ballast and running the required connections to the second electrode outside of the glass tube. For example, this would also be possible with wires that are inserted in a longitudinal groove, in order to protect them from damage.
It is technologically much simpler to apply conductive coatings to the glass tube as connection lines, which are additionally covered with a protective layer.
The solution is simplified in that the number of required connection lines is reduced. This can be achieved according to the invention in that the second electrode is not heated, both ends of the coiled electrode then being simply connected to each other. This method is feasible, but, among other things, leads to a shortening of the lifetime of the lamp. It is better to use so-called xe2x80x9cunheated, cold electrodesxe2x80x9d, which are equipped with a large amount of emitter paste and were deliberately developed with other measures for an unheated, cold start.
In order to make possible contact with the metal coatings nonhazardous, it is recommended according to the invention that these be made potential-free by a protective capacitor. Since transmission of the lamp current occurs with a high frequency to 100 kHz, only small capacitance values are required, which entail no contact hazard for a low line frequency of 50 or 60 Hz, especially if additional insulation protects against contact.
It is expedient to equip the lamps in the region of the second electrode, i.e., on the xe2x80x9cfreexe2x80x9d end, with means to mount or support the lamp.
A significant additional improvement consists of providing the housing of the electronics with a base for insertion in a light socket. This produces a xe2x80x9ccompactxe2x80x9d fluorescent lamp with integrated electronics, as are present in large numbers on the market in the small lamps for household use with a base on one side. In these lamps, the one-sided base is achieved in that the gas discharge vessel, i.e., the glass tube, is either bent in a U-shape or melted together from two individual glass tubes, a method that cannot be rationally used in long glass tubes.
The subsequent figures serve for understanding of the inventive concept and its progressiveness. They cannot describe all the details of the invention, since there are numerous manufacturing variants and design possibilities that permit application of the invention.